Add test

Author: VincentLanglet

tests/PHPStan/Analyser/nsrt/bug-4890-php8.php

@@ -0,0 +1,23 @@
+<?php // lint >= 8.0
+
+namespace Bug4890Php8;
+
+use function PHPStan\Testing\assertType;
+
+enum MyEnum
+{
+	case CASE1;
+	case CASE2;
+
+	public function someMethod(): bool { return true; }
+}
+
+class HelloWorld
+{
+	public function withEnumCase(\UnitEnum $entity): void
+	{
+		assertType('class-string<UnitEnum>', get_class($entity));
+		assert(method_exists($entity, 'someMethod'));
+		assertType('class-string<UnitEnum&hasMethod(someMethod)>', get_class($entity));
+	}
+}